Produce a Latex diagram

I require the figure in the attached PDF to be produced as a Latex file, suitable for processing with xelatex. Only the figure is needed (figure 1) with the associated text next to it, but not the paragraphs above and below it. It will eventually be inserted into another document using a custom class, also attached. The diagram does not need to be exactly the same, just a good representation. It is more important for the resultant Latex file to be as simple as possible. The Freelancer can choose suitable packages as required (e.g. Tikz), but they must be readily available, and preferably already distributed within a Debian package (e.g. texlive-pictures or texlive-latex-extra)